In message , Nigel
Hewer writes

Pump overrun devices are usually part of the boiler rather than
programmer.
Of course Servowarm tended to have a mind of their own. ;-)
I'm just wondering if his timer is a Horstman 424 - one version of
which
(the emerald?) had a bimetalic pump overrun integrated into it
Thanks for everyones comments.
My system does not have a room stat and on closer inspection of the
timeclock have noticed a bi-metallic strip that is broken (thanks
geoff) Could I replace this or replace the timeclock? Any ideas where I
might get one?



If there had been one person in the UK who might have had one, it would
have been me

I don't

You are (as they say) buggered

there are some solutions, but you're better off being told by one of the
fitters who frequent this NG


--
geoff